The invention has application to the reduction of vibrations in mechanical components that undergo acceleration in use, for example in the mechanical positioning of a process head in different directions in the manufacture of semiconductor devices where high accuracy is required.
One such manufacturing process is wire bonding, where a machine moves a wire bonding head in orthogonal X, Y and Z directions, under programmed computer control, to successively position and then attach and electrically connect a series of wired connections between contact pads on semiconductor wafers and corresponding connection points on their associated supporting lead frames.
In known bondhead assemblies, there are many vibration peaks observed in the frequency response function due to various resonances of individual mechanical components and in the overall system. Resonances from the bondhead can pass to an XY table assembly adapted to move the bondhead along X- and Y-axes, and adversely affect its performance. In particular, the wirebonder exhibits many resonances in the Z-axis due to components such as the wireclamp and ultrasonic transducer. These vibrations can limit or degrade the accuracy or repeatability of the positioning of the head, and therefore the integrity and reliability of the wire bonds. This limits the speed at which the wire bonding machine can be satisfactorily operated.